add faq

docs/best_practices/custom_fields.md

@@ -22,7 +22,6 @@ The following data types are available:
 
 It is recommended to avoid using the data type `Text` to collect structured data. The text input is free of control and can, for example, be in any language. This helps you to increase the quality of the results when filtering for suitable contacts.
 
-
 ### Select
 
 If you are using required `Select` or `Multi Select` fields, contacts will be forced to select one of the provided answers. If you cannot ensure that one of the provided answers will be suitable, you can add an option `None of the others`.

docs/faq/index.md

@@ -0,0 +1,8 @@
+---
+layout: default
+title: FAQ
+nav_order: 5
+has_children: true
+---
+
+# FAQ

docs/faq/login.md

@@ -0,0 +1,16 @@
+---
+layout: default
+title: Registration and Login
+parent: FAQ
+nav_order: 2
+---
+
+# Registration and Login
+
+## Error message
+
+When signing up to the pool with an e-mail address already in use or resetting the password of an inexistant address, the response will always be a success message to hide the information about existing accounts from unauthorized persons.
+
+## Paused accounts
+
+Paused contacts can still log in but they won't be invited to new experiments anymore.